You may have seen @pfm discovery regarding prototype cards, I recommend you read his post which explains the situation very well.
So I decided to write a program to convert your pattern of yellow dots (which are in fact metadatas dropped during printing) into a readable format such as the print date, for example.
To clarify, this won’t work on all cards, as it depends on the quality of the scan, the printer in question and also the quality of the prototype card, so this tool is only useful if you’ve managed to recover your yellow dot pattern.
This is great; I don’t understand how some people can be so proficient. This offers incredible value as a tool for use within the TCG (and frankly, one the likes of CGC should be paying you for), but I’d imagine people will find great use of this outside the TCG too?
Each column is read top-to-bottom as a single byte of seven bits (omitting the first parity bit); the bytes are then read right-to-left. The columns (which we have chosen to number from left to right) have the following meanings
15: unknown (often zero; constant for each individual printer; may convey some non-user-visible fact about the printer’s model or configuration)
14, 13, 12, 11: printer serial number in binary-coded-decimal, two digits per byte (constant for each individual printer; see below)
10: separator (typically all ones; does not appear to code information)
9: unused
8: year that page was printed (without century; 2005 is coded as 5)
7: month that page was printed
6: day that page was printed
5: hour that page was printed (may be UTC time zone, or may be set inaccurately within printer)
4, 3: unused
2: minute that page was printed
1: row parity bit (set to guarantee an odd number of dots present per row)
